Polyurethane foams are conventionally prepared by reacting polyols with polyfunctional isocyanates with the use of a chlorofluoroalkane as a blowing agent. It is often desirable to prepare large quantities of the reaction mixture, known as master batches, for the preparation of foamed materials. Certain chlorofluoroalkanes conventionally used as blowing agents, including trichlorofluoromethane, trichlorotrifluoroethanes, and tetrafluorodifluoroethanes, appear to react in part with the primary and secondary polyols to form hydrogen chloride, aldehydes, ketones and other reaction products. These products formed by the reaction of the chlorofluoroalkanes with the polyols adversely effect the properties of the polyurethane foams. Accordingly, it has previously been found desirable to incorporate stabilizers in such mixtures to prevent the reaction of blowing agent and polyurethane precursors. Typical of those stabilizers previously used are those shown in Bauer, U.S. Pat. No. 3,183,192.
While the stabilizers previously used to inhibit undesirable reactions in polyurethane foam precursors have been effective in their intended use, the stabilizers often result in an objectionable odor that persists in the completed foam when rigid foams are prepared.